Explicit note about pointerrawmove having an empty predicted event li…

…st (#383)

* Add explicit note about pointerrawmove having an empty predicted event list

* Soften language to not make it sound like a requirement

index.html

@@ -1063,6 +1063,10 @@ <h2><dfn>Predicted events</dfn></h2>
             <code>PointerEvent</code>s). If this event is a <code>pointermove</code> event, it is a sequence of
             <code>PointerEvent</code>s that the user agent predicts will follow the events in the
             <a>coalesced event list</a> in the future; otherwise it is an empty list.</p>
+            <div class="note">
+                <p>While <code>pointerrawmove</code> events may have a non-empty <a>coalesced event list</a>,
+                their <a>predicted event list</a> will, for performance reasons, usually be an empty list.</p>
+            </div>
             <p>The number of events in the list and how far they are from the current timestamp are determined by
             the user agent and the prediction algorithm it uses.</p>